By improving air quality, reducing levels of certain pollutants could prevent …

If a group of scientists announced that reducing emissions of some pollutants would prevent global warming, it wouldn’t make headlines—we’ve been hearing that for years when the pollutant is carbon dioxide. However, if they added that those reduced emissions would also prevent millions of premature deaths per year and increase annual crop yields by tens to hundreds of millions of tons, you would probably take notice. But the part that will really blow your mind—and what might make some people reconsider their stance—is that all of this could be done at a profit.

A large group of scientists identified 14 emissions reduction measures—out of around 400 considered—that primarily reduce ozone and black carbon (BC; think soot) using existing technology. The study was authored by Drew Shindell, of NASA Goddard and Columbia University, who had 23 coauthors from a total of 13 different institutions around the world (from countries including the US, UK, Italy, Austria, Thailand, and Kenya). The group concluded that the economic benefits of improved air quality and diminished global warming exceed the typical costs of these 14 approaches.

Carbon dioxide (CO2) has been the focus of most climate change studies and is one of the most significant greenhouse gasses because of its long lifespan in the atmosphere. Ozone and BC don't stay in the air as long, but they cause both warming and decreased air quality, which directly impacts human health and agriculture productivity. Because they remain in the atmosphere for only a few weeks, control measures that target them would quickly produce noticeable improvements in the climate and air quality.

The authors started out by evaluating existing technologies that improve air quality, and ranked them according to how large an impact they had on climate change. They discovered that the top 14 measures were able to produce about 90 percent of the total possible reductions that could be achieved using all measures combined.

Of the 14 emissions reduction measures, half of them target methane (CH4), an ozone precursor. These targeted areas including coal mining, oil and gas production, long-distance gas transmission, municipal waste and landfills, wastewater, livestock manure, and rice paddies. The remaining seven target BC emissions through technological approaches that reduce incomplete combustion, which can occur when there isn’t enough oxygen to burn all the fuel, usually due to inefficient technology. These inefficiencies show up in diesel vehicles, biomass stoves, brick kilns, and coke ovens. BC can also be targeted by regulations banning agricultural waste burning, the elimination of high-emitting vehicles, and adoption modern cooking and heating methods.

By pairing these emissions reduction approaches with a complex climate model, the researchers found that the predicted global warming by 2030 would be reduced by approximately 0.5°C, which would limit the increase to about 1.2°C from the 1890-1910 preindustrial mean temperature. The current international limit for global temperature rise is 2°C, which the authors here say requires both significant CO2 and CH4 + BC emissions reductions—neither alone will prevent us from passing that limit.

In addition to the decreased global warming potential, reduction of ozone and BC in the atmosphere—or more specifically the troposphere, the lowest level of the atmosphere—would have other benefits. It should improve global food crop yields (including wheat, rice, maize, and soy) and prevent premature deaths due to air pollution. The authors' calculations showed that approximately 53 million metric tons of crops could be saved (valued at around $8.2 billion) and 0.7-4.7 million deaths could be avoided each year in 2030 and beyond. These measures would also result in improved indoor air quality, which is a bit harder to calculate due to limited data; the authors estimate an additional 373 thousand lives a year in India and China would be saved.

One important note to these results: there would be further crop yield benefits from the limited climate change, but this study didn’t consider these indirect results. The agricultural benefits calculated here resulted directly from reduced levels of ozone and BC in the troposphere.

Now for the cost of all this: they estimated that 2030 emissions could be reduced by 110 teragrams (Tg, 1012 grams) of CH4 with costs below $1500 per metric ton of CH4. Accepting a somewhat lower target, 90 Tg, would cost even less: $250 per metric ton. The economic benefit of reducing these emissions, on the other hand, is conservatively about $1100 per metric ton of CH4 and potentially as high as $5000 per metric ton. Most of the reductions, then, produce benefits outweighing the costs.

The BC improvements, mainly in brick kilns and clean-burning stoves, actually lead to net cost savings through efficiency improvements. Regulations on vehicle emissions and agricultural waste burning would require political capital rather than actual money. The total benefits of BC improvements work out to around $5.4 trillion, mainly health-related, so a significant profit is also likely here.

Finally, the authors identified the regions that would benefit the most from these measures. While the avoided warming is fairly well spread out across the globe, central and northern Asia, southern Africa, and the Mediterranean in particular would be helped. The benefits in these areas come in large part from reduced albedo forcing on snow and desert areas thanks to lower BC levels. Albedo refers to the reflection of light from the earth’s surface; bright surfaces reflect more light while darker surfaces (such as those covered in BC particles) absorb more sunlight. With the higher albedo, snow and ice would last longer into the year in these areas.

Developing nations in Asia and Africa would avoid the most premature deaths due to cleaner air. If measuring increased crops by total metric tonnage gains, China, India, and the US would benefit the most here, but the Middle East would see the greatest improvement by percentage (due to large potential ozone reductions).

This study, unlike most climate change studies that emphasize reduction of CO2 emissions, demonstrates that a small number of air-quality improvement measures could also have a large impact on global warming. These techniques, all of which could be implemented with current technology, provide practical benefits for food crops and human health that outweigh the costs in most cases, and simultaneously slow the rate of climate change. If policy makers know that following this plan makes economic sense, it might have a better chance of being enacted—and we might be able to limit climate change.

Ars Science Video >

A celebration of Cassini

A celebration of Cassini

Nearly 20 years ago, the Cassini-Huygens mission was launched and the spacecraft has spent the last 13 years orbiting Saturn. Cassini burned up in Saturn's atmosphere, and left an amazing legacy.

Kyle Niemeyer
Kyle is a science writer for Ars Technica. He is a postdoctoral scholar at Oregon State University and has a Ph.D. in mechanical engineering from Case Western Reserve University. Kyle's research focuses on combustion modeling. Emailkyleniemeyer.ars@gmail.com//Twitter@kyle_niemeyer

Don't hold your breath. This would require people and politicians to acknowledge that climate change and pollution do, in fact, exist. A key component of the radical conservative religion is that global warming is a hoax. I think you've got the right idea, but your article makes the mistake of assuming that Republicans and Teabaggers who have spent their careers denying climate change can be persuaded by concrete facts and rational argument.

If policy makers know that following this plan makes economic sense, it might have a better chance of being enacted—and we might be able to limit climate change.

Avoiding severe climate change in the first place makes economic sense period, but that hasn't stopped politicians from finding excuses to delay action and make things more expensive in the long run.*edit* Beaten to the punch!

This problem will come down to business and governmental policy change. Long term gains will not be viewed favorably if it changes the status-quo and requires us to spend money now to make money later. That little problem may mean we are doomed to continue in the current epic fail mode. The dinosaurs were none to bright and we seem destined to repeat their fate.

One problem is that the costs to improve efficiency are very specific (spend money) but the benefits are less tangible( better crop yields, fewer deaths etc). So the people spending the money mostly won't notice (except for the cases with reduced fuel).It looks like governments will have to make unpopular decisions to increase regulation.

The difficulty with these aggregate cost/benefit analyses is that the costs fall on one group, while the benefits primarily go to another, and so aggregating to a positive value is not sufficient to encourage change.

Why do they have to estimate it 19 years out, when we have actual measured emissions today? It makes me think that they don't want to be held accountable if people actually use real-world numbers. Either that or there is a non-linearity to their estimation curve that would make today's estimates look piddly.

" ..The total benefits of BC improvements work out to around $5.4 trillion, mainly health-related, so a significant profit is also likely here..."

A worldwide investment in 10000 new mass produced nuclear reactors at a cost of less than $15 trillion over the next 15 years would be paid for by and would end fossil fuel use valued at around $3T annually, eliminate most air pollution saving millions of lives, end the global warming/ peak oil problem with a 100% elimination of GHG's within a ten year time frame, and is a great investment making the economy more efficient, a wonderful job producing economy boost, and requires only a small part of our industrial capacity. $15T with $8B (3+5)in payback gives a TWO year payback period and over a 50% rate of return on investment.

Deniers and Warmists both could embrace it.

There are no renewable energy schemes that can make even the tiniest dint in GHG emissions with their need for 100% name plate backup from inefficient fossil fuel sources run inefficiently, until a not yet invented storage scheme becomes available many decades in the future if ever.

A modern version of FDR's depression ending New Deal building nuclear plants would solve the US energy needs in 10 years or less if ever the cowardly Obama could find the cojones to actually do something instead of just cowering in his darkened oval office.

2500 new mass produced nukes scattered around the US at $3300B financed by the $800B paid every year into the coffers of Big Oil/Coal for their deadly products would carry all US energy needs. No need even for transmission builds. Add this carbon cost to it and the payback is in the first two years.

Factory produced Nuke power is by far the least expensive form of energy at less than 2.5 cents a kwh . Many Republican Senators like Alexander and McCain see the need for 200 new factory produced nuke plants over the next 15 years in the US basically a trivial exercise requiring a tiny portion of recession freed industrial capacity. In fact the construction of 2500 nukes by a federal agency like FDR's Bonneville or TVA over the same time to replace all fossil fuels would be quite feasible ending the recession and generating 40% rates of return on investments to the nation as a whole for a carbon to nuclear conversion.

GTL plants like Shell's new Qatar plant using natural gas to make diesel at $35 a barrel and easily adaptable to nuclear hydrogen/atmospheric CO2 as feedstock, would provide liquid fuels.

The effort to replace all fuel sources with nuclear would be similar to the industrial effort required to produce Liberty ships or Sherman tanks in WW2 - easy since our economy today has ten times the industrial capacity 20% idle. The rate of return on that investment is over 50% per annum to the nation as a whole.

With a fossil to nuclear conversion over fifteen ten years well within our idle industrial capacity, rates of return of 40% per annum to the nation as a whole, and a fossil to renewable conversion utterly impossible financially, industrially, and politically,it is not only incredibly stupid governments and leadership that is wrecking warming/air pollution reduction efforts, but worse the ecofascist movement led by Greenpeace with its equally stupid malevolent even pathological opposition to nuclear power.

The biggest problem is a nuclear conversion will put Big Oil out of business and they buy a lot of politicians and antinuke media support to ensure that doesn't happen

The pollution deaths of three million folks worldwide every year and billions more when they cause us to slide over the fast approaching climate precipice are the hapless pawns in this dirty game.

The difficulty with these aggregate cost/benefit analyses is that the costs fall on one group, while the benefits primarily go to another, and so aggregating to a positive value is not sufficient to encourage change.

This. And the adversely affected group is an established power, while the beneficiaries are spread out and non-organized.

Most new technologies suffer from the same issues. The supporters of new, not yet established technologies don't have power yet, while incumbents do. The incumbents flex their muscles to fashion legislation to benefit themselves at the expense of the future companies. This is why there is a ton of money going towards protecting the interests oF the established media people at the expense of new media companies.

Don't hold your breath. This would require people and politicians to acknowledge that climate change and pollution do, in fact, exist. A key component of the radical conservative religion is that global warming is a hoax. I think you've got the right idea, but your article makes the mistake of assuming that Republicans and Teabaggers who have spent their careers denying climate change can be persuaded by concrete facts and rational argument.

Spoken like a truly enlightened individual. I crave more of your amazing insight and look forward to your newsletter.

Perhaps you'd care seal yourself into a room where you can get all the oxygen you want, but the CO2 has to be allowed to build up. You know, like the Apollo 13 command module.

There ya go again using logic. It doesn't work. The religious conservative deniers are just plain crazy. The only difference between those folks and Taliban is a fucking TURBAN. They'd have a totalitarian regime implemented here, if given the chance to seize power.

The difficulty with these aggregate cost/benefit analyses is that the costs fall on one group, while the benefits primarily go to another, and so aggregating to a positive value is not sufficient to encourage change.

This is true, to a certain extent, and the authors admit as much in the paper.

However, some of the benefits do go to the nations/regions where the costs occur. The largest reduction in methane emissions would be from coal mining in China; followed by oil and gas production in Central Africa, the Middle East, and Russia; coal mining in South Asia; and municipal waste in the US and China.

(note that the US is only up there for municipal waste... most of the changes need to occur in other parts of the world, for the ozone and black carbon reductions here)

These are mainly the same areas that would see the benefits of increased crop yields and reduced deaths. The US, for reducing methane emissions from landfills, could see over 6 million tons in improved crop yields.

Don't hold your breath. This would require people and politicians to acknowledge that climate change and pollution do, in fact, exist. A key component of the radical conservative religion is that global warming is a hoax. I think you've got the right idea, but your article makes the mistake of assuming that Republicans and Teabaggers who have spent their careers denying climate change can be persuaded by concrete facts and rational argument.

Define irony, Somebody on an ARS Comment thread commenting about facts and rational argument and can't even formulate a logical thought without partisan hackery laced with sexual pejorative. FAIL

Sorry, but the Apollo 13 analogy fails. A tiny spaceship is not an ecosystem. The guy above seemed to be referring to plants taking in CO2, and the best response is that you'll die in a spaceship? Apollo 13 didn't have more plants than humans onboard, but planet earth does. I know it's more complicated than that, and that's my point.

The problem I have is just this. People take a side and then proceed to act like the other side is dumb. This is called politics, and politics often produce terrible ideas to real problems. For some reason everyone just gets angry and attacks.

My issues aren't about GW, or even the causes. My issues are with the solutions that throw good money after bad, with no real beneficial outcome. Google the green impact zone in Kansas City. Lots of tax dollars spent to improve the efficiency of old homes (and create jobs), and was played up as a bright spot for the stimulous bill. However, the project is mostly a failure. The local paper wrote a scathing fact-finding editorial about it that has since "disappeared." It mentioned things like shoddy work, overbilling, and lack of interest, but all the administrative budget is being spent. I think when most people see costly failures like these, they are pretty reluctant to agree to more policy on the issue.

Sorry, but the Apollo 13 analogy fails. A tiny spaceship is not an ecosystem.

Actually it is, it's technically a microhabitat. Functions usually served by organisms were replaced by machinery but the outcome is the same on short timescales. CO2, which has harmful effects, had to be filtered out otherwise it changes the environment (whether that's Earth's biosphere or the air in a moon mission module) in a detrimental way. Plants, oceans, and rocks do this on Earth, but they can't keep up with all natural emissions + human emissions (that's why CO2 levels are rising). We have an excessive amount of CO2 in the system, and the excess is coming from human activities. The excess changes the dynamics of the environment (in AGW by warming the atmosphere, raising sea levels, and changing the pH of the ocean, among other things). There is no reason NOT to consider it a pollutant. This isn't just some wacky environmentalist idea, this is the conclusion of the US Supreme Court as well, and the findings of the EPA.Maybe you don't consider these kinds of small, artificial life-support environments to be "ecosystems," but I think that's largely a failure on your part rather than a strict observance of meanings. I can set up a bare tank and put a goldfish in it: that tank becomes the ecosystem even if it lacks plants or soil bacteria or a constant population of life food, or whatever. When I do this, though, to keep the ecosystem healthy I have to take over the normal functions of organisms in the ecosystem: I have to remove harmful wastes and provide nutrients.

Perhaps you'd care seal yourself into a room where you can get all the oxygen you want, but the CO2 has to be allowed to build up. You know, like the Apollo 13 command module.

There ya go again using logic. It doesn't work. The religious conservative deniers are just plain crazy. The only difference between those folks and Taliban is a fucking TURBAN. They'd have a totalitarian regime implemented here, if given the chance to seize power.

As qualifying for two of the three (I'm not a denier), I think you've gone a bit overboard. Of course, I am crazy because even if I form an opinion, I am willing to listen to other data and change that opinion. For one, I am all for reducing and/or eliminating pollution, increasing use of green technology, and moving away from fossil fuels.

Then again, there are many who say the atheist liberal environmentalists want to have a totalitarian regime implemented here as well.

The problem I have is just this. People take a side and then proceed to act like the other side is dumb. This is called politics, and politics often produce terrible ideas to real problems. For some reason everyone just gets angry and attacks.

My issues aren't about GW, or even the causes. My issues are with the solutions that throw good money after bad, with no real beneficial outcome. Google the green impact zone in Kansas City. Lots of tax dollars spent to improve the efficiency of old homes (and create jobs), and was played up as a bright spot for the stimulous bill. However, the project is mostly a failure. The local paper wrote a scathing fact-finding editorial about it that has since "disappeared." It mentioned things like shoddy work, overbilling, and lack of interest, but all the administrative budget is being spent. I think when most people see costly failures like these, they are pretty reluctant to agree to more policy on the issue.

+1

Most people are willing (in my experience anyway) to try to make the world a better place. It's the government taking all that money saying "we'll do it!" and then wasting it through graft, corruption, and overall lack of caring beyond the next election.

Most people are willing (in my experience anyway) to try to make the world a better place. It's the government taking all that money saying "we'll do it!" and then wasting it through graft, corruption, and overall lack of caring beyond the next election.

Except the government is just made up of people. Your statement makes it sound like it's an otherworldly machine designed to ruin the plans of good people like you and me. It's not. Those people doing the graft, corruption and overall lack of caring, if they didn't have a government to help them perpetrate (what you see as) their evilness would just find another way to enrich themselves at the expense of others. Probably with a lot less oversight, there being no government and all.

When you're talking science, appeal to the science. When you're talking law, appeal to the law. I did both because it was appropriate for this issue to tackle the science of CO2 as a pollutant and the legal framework around it.

We goofed. Climate blame was a tragic exaggeration and even Obama never even mentioned it in his state of the union address. What is worse than a climate crisis, a comet hit?Occupywallstreet's list of demands has dropped climate change because of the required bank funded and corporate run CARBON TRADING STOCK MARKETS and taxing the air we breathe.The new denier is anyone who still believes anyone believes. Even the scientists, all countless thousands of them still magically sit on their thrones instead of marching and ACTING like a crisis was real.IT WAS A CONSULTANT'S WET DREAM and it made fools out of all of us.

Remaining Doomer,.Now don't get emotional and upset with us but the danger isn't real after all, because CO2 fears were exaggerated. Don't be disappointed, it’s good news that the worst crisis imaginable, a climate crisis isn't real. No worries. It wasn't a hoax or a crime, it was exaggeration. And if you spent as much time investigating the mountains of doubt about CO2 fears as you do chanting “it is real”, you could stop being an END OF THE WORLD clown. The danger has passed but pollution is real, we all get it. Now get ahead of the curve.

Most people are willing (in my experience anyway) to try to make the world a better place. It's the government taking all that money saying "we'll do it!" and then wasting it through graft, corruption, and overall lack of caring beyond the next election.

Except the government is just made up of people. Your statement makes it sound like it's an otherworldly machine designed to ruin the plans of good people like you and me. It's not. Those people doing the graft, corruption and overall lack of caring, if they didn't have a government to help them perpetrate (what you see as) their evilness would just find another way to enrich themselves at the expense of others. Probably with a lot less oversight, there being no government and all.

True, the government is just made of people. Like corporations are made of people (though not a person itself). I am not against government per se, and see the need for oversight. Maybe I am just saying that since we the people are the "boss" and therefore the overseers of the government, maybe we the people should do a better job.

And just because they would find another way to enrich themselves does not make what they are doing right to begin with.

The difficulty with these aggregate cost/benefit analyses is that the costs fall on one group, while the benefits primarily go to another, and so aggregating to a positive value is not sufficient to encourage change.

Perhaps you'd care seal yourself into a room where you can get all the oxygen you want, but the CO2 has to be allowed to build up. You know, like the Apollo 13 command module.

That doesnt make it a pollutant. I could put you in a tank filled to the brim with pure mountain spring water and you would be dead in minutes, but that doesnt make spring water a pollutant.

I could say the same for brine, maybe the waste brine from desalinization. But pump enough of that brine into a freshwater aquifer and see how quickly it becomes a pollutant. The opposite is true, also! Pump enough of your "pure mountain spring water" into a saltwater fish rearing tank and see if it doesn't cause problems. The artificially introduced excess of whatever causes things in the ecosystem to change for the worse. Nitrogen fertilizer is also good for plants like CO2, right? Too much nitrogen-rich run-off into waterways causes deadly algal blooms ( not unlike one that laid up Sen. Inhofe for a while) and anoxic dead zones. How can nitrogen fertilizer be a pollutant if it's good for plants? Because too much of it causes problems. The point is that artificially changing the balance of things in an environment can make almost anything a pollutant, even CO2. I've already mentioned some of the observable, harmful effects our excess CO2 has had on the environment that warrants the label. This has already been recognized respecting the relevant laws (like the Clean Air Act) and scientific findings of fact (like the EPA's assessment).

↓ Moderation: I wasn't sure if this poster was sleep deprived or trolling, but now i'm sure it's trolling. (show post)

Y2Kyoto – CO2-EnvironMENTALismALGORE is my shepherd; I shall not think.He maketh me lie down in Greenzi pastures:He leadeth me beside the still-freezing waters.He selleth my soul for CO2:He leadeth me in the paths of self-righteousness for his own sake.Yea, though I walk through the valley of the shadow of reason, I will fear no logic: for thou art with me and thinking for me;Thy Gore’s family oil fortune and thy 10,000 square Gorey foot mansion, they comfort me.Thou preparest a movie in the presence of contradictory evidence:Thou anointest mine head with nonsense; my fear runneth over.Surely blind faith and hysteria shall follow me all the days of my life:and I will dwell in the house of ALGORE forever.

The problem I have is just this. People take a side and then proceed to act like the other side is dumb. This is called politics, and politics often produce terrible ideas to real problems. For some reason everyone just gets angry and attacks.

+1

Most people are willing (in my experience anyway) to try to make the world a better place. It's the government taking all that money saying "we'll do it!" and then wasting it through graft, corruption, and overall lack of caring beyond the next election.

Most people are willing to try and make the world a better place, but try asking them to spend more money for electricity, gasoline or any other everyday consumable and you'll get a negative response.

I think this is easily shown by the fact that (at least in Australia) there IS an option to pay more for 100% 'green power' from most electricity retailers, but the take-up is very slow. Surely if we all wanted to make the world a better place we'd be signing up to this?

I believe this is the biggest reason we're even having this climate change 'debate'. Australia has introduced a carbon tax, and many of my (rather progressive) friends are against it because "it's just the government taking our money". Ask them what they want instead and they'll say "the government should invest in solar and wind power". They don't realise that this will involve them paying higher taxes too (and probably more so than a more efficient price on carbon emissions), but it fits in with their views on how it should be solved, rather than seeing it (the carbon tax) as a method of paying for externalities that affect the following generations.

The bottom line is that we need a government to legislate for our future, because humans are not very good at understanding the long term benefits vs the immediate costs.

I remember a friend and I were in an argument about carbon taxes etc and he basically left himself in a trap where he said we should have green power but it shouldn't cost any more than coal power. It wasn't obvious to him that if said green power was as cheap as coal, then the transition should have already occurred. The idea that we're going to have to put more of our human / capital into energy production in a carbon-constrained world just didn't sit with him.

Compare this to the 'ozone' pollution crisis of the 80's - there were marginally more expensive options available to replace the CFCs in almost all applications - so it was an easy sell for something that was arguably even more conceptually difficult to prove was a real problem.

As to the 'government wasting our money' line - it is undeniably a distortion to the 'free market' to introduce controls on CO2 emissions - a pretty big one. And it will almost certainly produce grossly inefficient outcomes, especially if the government is tasked with directly solving the problem. But that doesn't mean it's not worth doing, because the alternative outcomes are far worse.

Incidentally this is why the argument for a pricing incentive (over direct action) is so strong, simply charge for CO2 emissions (tax or cap-n-trade) and you make the government's direct action very small and rely on the market to find the solutions. Governments who get involved in picking winners, or directly subsidizing particular forms of 'green' energy installation are doing themselves and their populations a big disservice. We've seen some of this in Australia too with these ridiculous feed-in rebates for solar panels on urban homes (60 c / kW-hr !). It looks good politically at the start, but you end up with a big distortion in your electricity market as the retailers are forced to pay outrageous prices for electricity supplied by pokey roof-mounted installations - guess who picks up the tab for that? What if everyone installed a solar system and expected 60 c / kW.Hr ? Who pays for that?

The solution is to force the companies to pay per tonne of CO2 emitted, and their investment decisions for new / replacement generation capacity will be influenced by these costs. I'm also not against throwing government money into R&D efforts to find solutions - it is a big problem and we all benefit from electricity and should make our contribution (through taxes) to the solution.

As to the 'government wasting our money' line - it is undeniably a distortion to the 'free market' to introduce controls on CO2 emissions - a pretty big one.

Actually, not factoring the costs of excess CO2 emissions ("externalities") is a huge distortion of the free market by making carbon-intensive power seem cheaper than it really is. Carbon pricing is a solution to this problem.

Most people are willing to try and make the world a better place, but try asking them to spend more money for electricity, gasoline or any other everyday consumable and you'll get a negative response.

I think this is easily shown by the fact that (at least in Australia) there IS an option to pay more for 100% 'green power' from most electricity retailers, but the take-up is very slow. Surely if we all wanted to make the world a better place we'd be signing up to this?

Im not so sure your example necessarily proves that people are unwilling to spend money to make the world a better place. I think its just as likely that the people who dont sign up for %100 green power simply dont believe that CO2 and global warming are really a threat, or as big a threat as you do. It might be that those people want to make the world a better place, but prefer to do it in some other way (like working at a food bank or cleaning up a oil spill or whatever)